This invention relates to an improved ebullated bed process. In the improved process, nominal 650.degree. F. + reactor effluent is examined by means of a microscope, the size and area percent of insoluble agglomerates is determined and reactor temperature adjusted therefrom. 2. Description of Other Relevant Methods in the Field
The ebullated bed process comprises the passing of concurrently flowing streams of liquids or slurries of liquids and solids and gas through a vertically cylindrical vessel containing catalyst. The catalyst is placed in random motion in the liquid and has a gross volume dispersed through the liquid medium greater than the volume of the mass when stationary. The ebullated bed process has found commercial application in the upgrading of heavy liquid hydrocarbons such as vacuum residuum or atmospheric residuum or converting coal to synthetic oils.
The ebullated bed process is generally described in U.S. Pat. No. Re. 25,770 issued Apr. 27, 1965 to E. S. Johanson.
U.S. Pat. No. 3,948,756 to R. H. Wolk et al. teaches pentane insoluble asphaltene removal in an ebullated bed process. In the process a residual oil feedstock is passed upwardly through a reaction zone containing a hydrogenation catalyst and a hydrogen rich gas at a temperature of 700.degree. F. to 800.degree. F. and a hydrogen partial pressure of 1000 psig to 3000 psig. Space velocity is 0.1 to 2.0 volume of feed per hour per reactor volume.
U.S. Pat. No. 4,457,830 to R. H. Kydd teaches the acid precipitation of preasphaltenes in an ebullated bed process. In the process preasphaltenes are precipitated from a bottoms fraction boiling above about 950.degree. F. by precipitation with 3 to 10 weight percent of a selected acid.
U.S. Pat. No. 3,681,231 to S. B. Alpert et al. teaches an ebullated bed process in which the feed is mixed with a hydrocarbon diluent in a ratio of about 20 to 70 volume percent. The diluent of specified quality is said to improve the fouling of exchanger surfaces, pipe surfaces, valves and vessel walls.
U.S. Pat. No. 3,841,981 to E. T. Layng teaches an ebullated bed process for the hydrogenation of tar sand bitumen. Coke precursors are eliminated in a quenching stage.
Analytical methods are taught in U.S. Pat. Nos. 4,751,187; 4,752,587 and 4,388,408.